When you suggested this I right-away thought of my dad sleeping in his lazy-boy chair. If you put on a folding table, a recliner chair can sort of serve as a common piece of furniture. Really though, I guess it depends on what kind of furniture you mean to replace--chairs, beds, end tables, desk, dinner table yes. Entertainment center, probably no.

Also, a futon-couch is a multi-use piece in common use too.

But you really achieve little advantage in a multi-use piece of furniture--I think a real bed will always be more comfortable to sleep in. A real chair works better than sitting on the bed.

I expect you're thinking of efficiency in a really small living space?

The question is: Would the furniture be comfortable?